FB2025_05 , released December 11, 2025
FB2025_05 , released December 11, 2025
CV Term Report
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General Information
Term Johnston organ ID (Ontology) FBbt:00004178 (Fly Anatomy)
Definition Compound chordotonal organ of antennal segment 2 involved in hearing (Gopfert and Robert, 2002), direction-sensitive wind detection (Yorozu et al., 2009) and gravitaxis (Kamikouchi et al., 2009). The actin-filament rich basal tips of the Johnston's organ scolopidia connect to the inner surface of antennal segment 2, and the apical tips connect to the hook of antennal segment 3 (Gopfert and Robert, 2002). Its sensory neurons (Johnston's organ neurons or JONs) are connected to the Johnston's organ nerve (Kamikouchi et al., 2006), and predominantly innervate the antennal mechanosensory and motor center (AMMC). There are 477 +/- 24 cell bodies, arranged in a bowl shape lying vertically with the 'top' facing the lateral side, and forming a ring around the antennal nerve (Kamikouchi et al., 2006). JONs connecting to opposing sides of the hook are alternatively stimulated by stretching or compression according to the hook's oscillatory movement (Gopfert and Robert, 2002).[ FlyBase:FBrf0147122 FlyBase:FBrf0166419 FlyBase:FBrf0179481 FlyBase:FBrf0187921 FlyBase:FBrf0194812 FlyBase:FBrf0207559 ]
Also Known As "JO" ; "Johnston's organ"
Comment Yorozu et al., 2009, identify tonically activated Johnston's organ neurons that respond to forward or reverse deflection of the antenna. Genetic ablation of these neurons inhibits wind-induced behavioral responses without impairing hearing. Further, by expression of tetanus toxin, Kamikouchi et al., 2009, identify the same neuronal population as essential for gravitaxis behavior.
Links to External Ontologies
VFB:FBbt_00004178
Annotations
Records annotated with this term OR any of its CHILD TERMS
Records annotated with this exact term (annotations to child terms are NOT included)
Data Class Field Records
Alleles (FBal)  PHENOTYPE_MANIFEST_IN      44
Insertions (FBti)  EXPRESSION_STAGE_TISSUE_POSITION       4
Insertions (FBti)  PHENOTYPE_MANIFEST_IN       7
Constructs (FBtp)  PHENOTYPE_MANIFEST_IN      16
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 Full annotation statements 
Relevant FlyBase reports
 Alleles Genes Images Insertions Constructs
 Johnston organ (all annotations which use CV term, excluding "NOT" statements)      44     28      5     11     27
     Johnston organ | adult stage       5       --       --       1      1
     Johnston organ | heat sensitive       1       --       --       --       --
     Johnston organ | P-stage       2       --       --       --       --
     Johnston organ | P-stage | somatic clone      14       --       --       --      12
     Johnston organ | third instar larval stage       6       --       --       2       --
Spanning Tree (Parents/Children)
Only view relationship:
adult sense organ
 |__adult chordotonal organ_________
mechanosensory sensory organ        |
 |__auditory sense organ____________|
chordotonal organ                   |
 |__adult chordotonal organ_________|
adult antennal sense organ          |
 |__antennal segment 2 sense organ__|
compound sense organ                |
 |__internal compound sense organ___|
                                    Johnston organ  115 rec.
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Is a antennal segment 2 sense organ
internal compound sense organ
auditory sense organ
adult chordotonal organ
Part of
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Synonyms
  • "chordotonal organ of antennal segment 2" RELATED
    "JO" EXACT[ FlyBase:FBrf0210248 ]
    "Johnston's organ" EXACT
Secondary IDs
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VFB:FBbt_00004178